An empirical study of electron backscattering from thin films

Empirical fits to data are obtained which determine the backscattered electron coefficient for films of arbitrary thickness and electrons of normal incidence over the energy range 20–53 keV for the elements Al, Cu, Ag, Au, and Bi. From this is derived a ’’universal’’ fit which describes with reasonable accuracy the backscattered electron coefficients of Be, Al, Cu, Ge, Ag, Au, Pb, and Bi over a somewhat larger energy range. By extension, it should predict the coefficients of other elements over at least the atomic number range Z=4–83. An expression is suggested for predicting the backscattered electron coefficient for films of arbitrary thickness and composed of compounds of several elements. Approximate agreement with experiment is obtained.